How to Make a Countdown Clock Using JavaScript?

[Dr. Phil]

How do you make a countdown clock using basic JavaScript commands; such as, dateobject.
Write a webpage that displays continuously up-to-the-second how many hours, minutes, and seconds are left in todays's class. Assume the class ends at 8:45pm on the current day.

Here is an example of what your page would look like:
(except the time will be different and change every second)

Time Left in Today's Class

1:35:42